PPP's monthly look at the 2016 Republican field for President finds essentially a 4 way tie at the top- Marco Rubio has 16%, Jeb Bush and Chris Christie 15% each, and Rand Paul 14%. Paul Ryan at 9%, Ted Cruz at 7%, Rick Santorum at 5%, Bobby Jindal at 3%, and Susana Martinez at 1% round out the potential candidates we tested.